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Chad Johnson
Asked: 2009-10-16 16:27:36 +0800 CST

为什么我的反向 SSH 隧道突然死掉了？

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从我所有的客户端计算机到我的服务器，我已经建立了大约一年的持久隧道。据我所知，我已经有几个月没有更新我的服务器或更改任何配置文件了。突然，我的所有客户端计算机的隧道都停止工作（我为每台计算机使用不同的端口）。

我使用 RSA 密钥。我已经在每台计算机上多次重新生成它们。

当在“ps aux”输出中找不到“[email protected]”时，我有一个脚本通过 Cron 作业运行以下内容：

ssh -p 2222 -g -T -N -x -f -R 2223:localhost:22 [email protected]

当我使用 -vvv 手动运行此命令时，我可以 ssh 进入服务器，然后 ssh 进入转发端口（ssh localhost -p 2223）就好了。然而，五分钟后，它就挂了。我使用 -vvv 在服务器上得到以下输出：

chad@zeus:~$ ssh localhost -p 2223 -vvv
OpenSSH_4.7p1 Debian-8ubuntu1.2, OpenSSL 0.9.8g 19 Oct 2007
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to localhost [127.0.0.1] port 2223.
debug1: Connection established.
debug1: identity file /home/chad/.ssh/identity type -1
debug3: Not a RSA1 key file /home/chad/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/chad/.ssh/id_rsa type 1
debug1: identity file /home/chad/.ssh/id_dsa type -1

当我远程登录到我得到的端口时

chad@zeus:~$ telnet localhost 2223
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

通常我会得到像“SSH-2.0-OpenSSH_4.3”这样的输出输出。

在客户端，我启动了隧道（通过 ssh -p 2222 -g -T -N -x -f -R 2223:localhost:22 [email protected]），我得到以下详细输出：

OpenSSH_5.1p1 Debian-5ubuntu1, OpenSSL 0.9.8g 19 Oct 2007
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to my.hostname [68.6.214.39] port 2222.
debug1: Connection established.
debug1: identity file /home/chad/.ssh/identity type -1
debug3: Not a RSA1 key file /home/chad/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/chad/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/chad/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.7p1 Debian-8ubuntu1.2
debug1: match: OpenSSH_4.7p1 Debian-8ubuntu1.2 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.1p1 Debian-5ubuntu1
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,[email protected],aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,[email protected],aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,[email protected],aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,[email protected],aes128-ctr,aes192-ctr,aes256-ctr
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 120/256
debug2: bits set: 525/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: put_host_port: [68.6.214.39]:2222
debug3: put_host_port: [my.hostname]:2222
debug3: check_host_in_hostfile: filename /home/chad/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 3
debug3: check_host_in_hostfile: filename /home/chad/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug1: Host '[my.hostname]:2222' is known and matches the RSA host key.
debug1: Found key in /home/chad/.ssh/known_hosts:3
debug2: bits set: 534/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/chad/.ssh/id_rsa (0xb9b96ad0)
debug2: key: /home/chad/.ssh/identity ((nil))
debug2: key: /home/chad/.ssh/id_dsa ((nil))
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,gssapi-with-mic,gssapi,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/chad/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug2: input_userauth_pk_ok: fp 14:ff:10:40:31:88:05:bc:46:73:91:ef:58:70:cc:78
debug3: sign_and_send_pubkey
debug1: Authentication succeeded (publickey).
debug1: Remote connections from LOCALHOST:2223 forwarded to local address localhost:22
debug1: Entering interactive session.
debug1: remote forward success for: listen 2223, connect localhost:22
debug1: All remote forwarding requests processed

我的 .ssh 目录和文件的权限如下：

drwxr-xr-x  2 chad chad   4096 2009-10-15 00:03 .ssh

-rw-r--r-- 1 chad chad  408 2009-10-15 00:03 authorized_keys
-rw------- 1 chad chad 1675 2009-10-14 10:09 id_rsa
-rw-r--r-- 1 chad chad  393 2009-10-14 10:09 id_rsa.pub
-rw------- 1 chad chad 2210 2009-10-14 11:27 known_hosts

此外，如果我在客户端上“killall ssh”，然后 telnet 到端口 2223，我仍然会收到响应：

chad@zeus:~$ telnet localhost 2223
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

我彻底糊涂了。任何想法为什么会发生这种情况？

ssh

1 个回答

  1. Best Answer

    您的服务器周围的网络设置是否有任何变化？我已经看到当流量通过的路由器或防火墙在没有流量时不保持 TCP 连接状态时会发生这种情况。

    尝试将此添加到服务器上的 ssh_config 中：

    ServerAliveInterval 60

    这将每分钟通过 ssh 连接发送一些数据（它不会干扰您的隧道），因此无论您的连接超时，都不会忘记它。如果它不再响应，它会自动终止您的 ssh 隧道，这将允许您现有的脚本重新连接。

    • 5

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